(CNN) -- Shark experts began arriving in the Egyptian resort of Sharm el-Sheikh on Tuesday to investigate what led to four attacks over the last week that killed a German woman and injured three snorkelers, officials said.

The behavioral experts will form an advisory team to assess and advise on the best course of action following the attacks, according to Jochen Van Lysebettens, general operations manager of the Red Sea Diving College in Sharm el-Sheikh.

The tab for the expert advice is being picked up by the Ministry of Tourism.

Van Lysebettens said the reason behind the shark attacks needs to be determined in order to stop it.

Sharm el-Sheikh beach will remain closed until the shark responsible for Sunday's fatal attack is found, according to Egypt's Interior Ministry.

A 70-year-old woman, a regular guest at the resort, was snorkeling near a reef on Sunday when she was attacked, he said.

She called for help, and a lifeguard brought her to shore, but she had lost too much blood and resuscitation efforts failed, Van Lysebettens said. The woman's arm and leg had been severed, he said.

Amateur video of the attack showed splashing in shallow water as boaters looked on.

"It came at her," said the tourist and videographer, who asked not to be identified. The shark "kept biting her while she was screaming for help and trying to get away," he said.

The videographer's voice can be heard in the video, growing increasingly loud as the attack continued without apparent intervention from onlookers aboard nearby boats.

"Look at the blood," he said. "Oh my god."

After the incident, the Chamber of Diving and Watersports called on its members in the region "to stop any snorkeling activities happening from any boats or shore." The chamber is under the umbrella of the Egyptian Tourist Federation.

On Friday, two sharks were caught and killed near the South Sinai National Park on the Sharm el-Sheikh coast, according to the Chamber of Diving and Watersports.

The three injured snorkelers -- two Russian women and a man from the Ukraine -- were attacked in a 24-hour period November 30 and December 1, the chamber said.

Van Lysebettens said he is not a marine biologist, but many have speculated an oceanic white-tipped shark was responsible for the German woman's death, as well as the other attacks.

But the videographer of Sunday's attack said the shark he filmed did not have white markings on its fins.

Some are upset because the two sharks killed Friday are thought to be innocent. They were a mako shark and another oceanic white-tipped shark -- which did not match pictures taken by someone accompanying one of the injured snorkelers, Van Lysebettens said.

"This incident has clearly shocked our community, and the CDWS is continuing its investigation into why this may have happened," Hesham Gabr, head of the Chamber of Diving and Watersports, said in the statement. "It is clear from our initial discussions with shark behavioral experts that this highly unusual spate of attacks by an oceanic (white tipped) shark was triggered by an activity, most probably illegal fishing or feeding in the area."

Several divers in the area saw carcasses of dead sheep in the water last week, Van Lysebettens said. It's not known how they got there, he said, but they could have washed out to sea or fallen off a boat. The shark may have been attracted by the carcass, he said, and could now be attacking slow-moving things on the water's surface.

Van Lysebettens also said chumming could be to blame for the attacks. Chum is a mixture of blood and dead fish parts, which is used to lure sharks.